A number of systems generate heat which is exhausted from the system. One example of such a system is an automotive system wherein combustion of a fuel results in an exhaust with an elevated temperature.
Some approaches to recover the heat energy from exhaust have been investigated. For example, some approaches attempt to recover energy from exhaust systems using thermoelectrics to produce electricity by applying a temperature difference across a thermoelectric (TE) material. The generated electricity may be used to operate automotive electronics and ancillary systems thereby reducing load on the engine and associated energy management; thus improving fuel economy.
TE based systems typically include a heat exchanger which is used to extract heat from the hot exhaust. As the efficiency of the heat exchanger increases, more energy is removed from the exhaust resulting in increased generation of electricity. In known systems, however, increased efficiency of the heat exchanger is accompanied by increased backpressure which reduces the system efficiency.
Moreover, in known systems, higher efficiency heat exchangers are effected by increased size. As the size of the heat exchanger increases, the heat exchanger is subjected to increased thermal stresses. Additionally, in many systems, including automotive systems, space is a limited commodity.
What is therefore needed is a TE based system which exhibits increased efficiency. A TE system which does not significantly increase the pressure drop across the heat exchanger would be beneficial. A TE system which does not exhibit deleterious effects of increased stress and strain would be further beneficial. Additionally, a TE system which does not incur excessive space requirements would be beneficial.